Field of the Invention
The present invention relates to a liquid crystal display and a method for manufacturing the liquid crystal display.
Description of the Background Art
Liquid crystal displays each include a liquid crystal panel in which a pair of substrates sandwich liquid crystals therebetween, the substrates including an array substrate (hereinafter referred to as a “TFT array substrate” in some cases) and a counter substrate (hereinafter referred to as a “CF substrate” in some cases). The array substrate includes thin film transistors (TFT) as switching elements and pixel electrodes, and the counter substrate includes a color filter for color display.
Polarizing plates are bonded to external surfaces of the liquid crystal panel, namely, external surfaces of the TFT array and the CF substrate. In a polarizing plate bonding step of bonding the polarizing plates, the polarizing plates are bonded to the liquid crystal panel, for example, by mechanical aligning with respect to the outer shapes of the polarizing plates or by camera aligning with respect to the corner portions of the polarizing plates read by the camera.
The polarizing plate bonding step is premised on that optical axes such as absorption axes of the polarizing plates and a slow axis of a phase difference film fall within the range of a design tolerance to the outer shapes of the polarizing plates.
However, in a case where the optical axes such as the absorption axes of the polarizing plates and the slow axis of the phase difference film do not fall within the range of the design tolerance to the outer shape, desired optical properties cannot be obtained.
Even in this case, high quality products can be manufactured if the polarizing plates are bonded such that the optical axes, for example, the absorption axes of the polarizing plates and the slow axis of the phase difference film, coincide with an alignment axis of the liquid crystals in the polarizing plate bonding step described above. In other words, the polarizing plates are preferably bonded with reference to the optical axes such as the absorption axes of the polarizing plates and the slow axis of the phase difference film.
However, an allowable tolerance of bonding positions of the polarizing plates is limited in the current circumstances in which narrow frames of liquid crystal displays are required, so that an angle allowing for rotations of the polarizing plates cannot be sufficiently obtained. Therefore, if priority is given to matching the rotation angle of the polarizing plates with an angle at which the optical axes coincide with the alignment axis of the liquid crystals, the polarizing plates protrude from the outer shape of the liquid crystal panel.
A technology to solve the problems is disclosed in Japanese Patent Application Laid-Open No. 2010-113109, for example. The technology disclosed in Japanese Patent Application Laid-Open No. 2010-113109 measures amounts of deviations of the optical axes of the polarizing plates, sorts them out, and corrects each group. In the case where the polarizing plates protrude from the outer of the liquid crystal panel, the protrusions of the polarizing plates from the outer shape of the liquid crystal panel are cut.
The technology disclosed in Japanese Patent Application Laid-Open No. 2010-113109 cuts the protrusions of the polarizing plates from the outer shape of the liquid crystal panel in the case where the polarizing plates protrude from the outer shape of the liquid crystal panel, but the protrusions of the polarizing plates from the outer shape of the liquid crystal panel are hardly cut after the polarizing plates are bonded to the liquid crystal panel.
To solve the problems, portions of the polarizing plates (hereinafter referred to as “potential protruding portions” in some cases) that are expected to protrude from the outer shape of the liquid crystal panel are conceivably cut in advance, but this case causes the problems below.
The polarizing plates are laminated on separators, so that the optical axes are hardly measured with accuracy. To accurately measure the optical axes, the separators need to be removed from the polarizing plates to measure the optical axes, and then the potential protruding portions of the polarizing plates need to be cut in advance. However, the polarizing plates that have once been processed into rectangle are additionally subjected to a cutting process, thereby increasing manufacturing steps and reducing production efficiency.
For the addition of the cutting process after the separators are removed or after the polarizing plates are bonded to the liquid crystal panel as described above, the problem in which the finishing touches are hardly applied to cut surfaces of the polarizing plates also arises.